Discrete item-based and continuous configural representations in visual short-term memory

ABSTRACT

Both discrete item-based and global configural information can be stored in visual short-term memory (VSTM). To characterize their contribution, the present study developed a dual-trace signal detection (DTSD) model consisting of a high threshold (HT) component for discrete item information and a continuous signal detection theory (SDT) component for configural information. We used an orientation change-detection task in which observers attempted to retain several orientations over a 1-s retention interval and then reported whether a cued item in the test array had the old or new orientation on a 6-point confidence scale. The resulting Receiver Operating Characteristics (ROC) curves were fit with the DTSD model, producing estimates of the two memory representations. In a series of experiments, we found that manipulations of configural encoding selectively affected the SDT component whereas the manipulation of item information selectively affected the HT component. Together these findings indicate that VSTM maintains a few discrete representations and continuous representation of configural information.

KEYWORDS:

• Short-term memory
• high-threshold
• signal detection theory
• capacity
• ROC

Acknowledgements

We would like to thank the constructive suggestions from Weiji Ma and two anonymous reviewers.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Weizhen Xie http://orcid.org/0000-0003-4655-6496

Additional information

Funding

This study was made possible by a postdoctoral fellowship to WZ (1F32MH090719) from National Institute of Mental Health (NIMH) National Research Service Award (NRSA) postdoctoral fellowship.